Food refiners are usually applied in the food conserves industry for separating fruit or vegetable juice or pulp from skins or peel, seeds and other waste present in the produce.
Reference is made in particular to a food refiner of a type comprising a fixed tubular sieve having an inlet for the produce to be treated and a discharge for the waste product, at the centre of which, and stretching from inlet to outlet, there is a rotor driven by a commandable rotatable shaft. The rotor radially bears a plurality of blades, each of which has one end which is very close to the surface of the sieve and causes the produce to move both in a centrifugal direction, pressing the produce against the sieve, and in an advancement direction towards the discharge, whereat the waste product exits. For this purpose the blades have a slightly inclined orientation with respect to the rotor axis. A casing is also provided, which surrounds the sieve and exhibits an outlet mouth for the refined product that has passed through the sieve and is then extracted from the food refiner.
Devices of this type exist in the prior art: one example is described in Italian Patent no. 67132A/77.
In order to be able to treat various produce, with equally varying consistency and fluidity, known food refiners usually operate by modifying the number of rotations of the rotor; this is not an entirely satisfactory system since it is not always possible, and never easy, to arrive at a number of rotations which on the one hand prevents a production of damp waste (meaning a waste of juice) and on the other avoids a too-energetic action which leads to deterioration in the quality of the final product.
A further drawback of the known food refiners is represented by the fact that the sieve and the blades exhibit different degrees of wear at various points thereof. The sieve tends to wear worse at its initial tract, and its holes tend to wear all on one side. The blades wear all on the one side too. This means that sieve and blades have to be substituted when only partially worn.
The main aim of the invention is to obviate the above-described drawbacks in the prior art, by providing a food refiner which gives an optimum treatment of the various types of produce used as well as enabling a longest-possible working life to be obtained of the parts most subject to wear, i.e. the sieve and the blades.
An advantage of the invention is that it acts differently on the produce in various zones of the food refiner itself, and can be commanded to change its working settings according to need and type of produce.
These aims and advantages and others besides are all achieved by the present invention, as it is characterised in the claims that follow.